1. Field of the Invention
The invention relates to a bogie for rail vehicles with a variable wheel track and more particularly to a bogie including a chassis carrying the body of the vehicle and four wheels connected to the chassis by articulated arms, each wheel being movable transversely relative to its support arm so that the wheel track of the bogie can be quickly adapted to the difference in track gage between some rail networks.
2. Description of the Prior Art
The document EP-B1-0 591 088 discloses a rail vehicle support bogie with a variable wheel track and including a central chassis and four oscillating arms joined to the central chassis. Each of the arms supports a transversely mobile set of bearings enabling the wheels of the bogie to be placed in two positions corresponding to two different track gages. However, this kind of bogie has the disadvantage that it cannot be adapted to receive traction motors. Accordingly, although with this kind of bogie it is possible to modify the wheel track of non-motor vehicles, it is still necessary to change the motor unit for a motor unit suited to the new track gage when a train is being readied for transfer onto a network having a different track gage. Changing the motor unit considerably complicates logistics and is not compatible with optimum use of rolling stock.
An object of the present invention is therefore to propose a variable wheel track bogie which can, without modifying its structure, be used as a support bogie or as a motor bogie, so that it can be fitted to either traction vehicles or non-motor vehicles.
Another object of the invention is to propose a variable wheel track bogie that is suitable for rail vehicles travelling at high speeds (in excess of 300 kph) and in particular new vehicles in which the motive power is divided between all of the bogies of the vehicles.
The invention provides a bogie for rail vehicles with wheels with a variable track and including a chassis supporting a body of the vehicle and four wheels connected to the chassis by articulated arms, wherein each wheel is movable transversely relative to the articulated arm to occupy at least two positions corresponding to two different track gages and the arms are able to pivot about a pivot with a movement damped by primary suspension members, wherein at least one articulated arm includes means for transmitting rotation of the wheel to a secondary shaft and the secondary shaft is constrained to rotate with a braking and/or traction system.
Particular embodiments of the bogie according to the invention can have one or more of the following features in isolation or in all technically feasible combinations:
the braking and/or traction system is carried by a member that is suspended relative to the articulated arm;
the braking and/or traction system is fixed directly to the chassis of the bogie;
the secondary shaft is connected to the braking and/or traction system by a universal joint;
braking and/or traction system includes a disk brake;
the braking and/or traction systems includes a traction motor;
the traction motor is fixed directly to the body of the vehicle;
each articulated arm supports a half-axle mounted on a transversely mobile set of bearings enabling the wheels of the bogie to be moved;
a cross-member is fixed between two articulated arms;
the transmission means consist of a gear train disposed in the articulated arm and the articulated arm has a hollow structure forming a transmission housing;
the secondary shaft is disposed near the pivot of the articulated arm.
The objects, aspects and advantages of the present invention will be better understood from the following description of one particular embodiment of the invention, given by way of non-limiting example and with reference to the accompanying drawings.